Player piano



Dec. 1, 1925. 1,563,977

A. G. GULBRANSEN PLAYER PIANO Filed June 23. 1920 4 Sheets-Sheet 1 M2 G Glflbmmem/ A. G. GULBRANSEN PLAYER PIANO Filed June 23, 1920 4 Sheets-Sheet 2 a (mm Wm 2 Z Y Dec. 1, 1925. 1.563.977

A. G. GULBRANSEN ts-Sheet 5 Dec. 1, 2 1,563,977 7 A. G. GULBRANSEN PLAYER PIANO Filed June 23, 1920 '4 Sheets-Sheet 4 way w s) Patented Dec. 1, 1925.

UNITED STATES PATENT QFFICE.

AXEL G. GUL BRANSEN, OF RIVER FOREST, ILLINOIS, ASSIGNOR TO GULBRANSEN COMPANY, OF CHIGAGO, ILLINOIS, A GORFORATION OF ILLINOIS.

PLAYER PIANO.

Application filed June 28, 1920. Serial No. 391,023.

To a7! whom it may 6011061 11.

Be it known that I, Axon G. GULBRAN- SEN, a citizen of the United States, residing at River Forest, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Player Pianos, of which the following is a full, clear, conelse, and exact description, reference being had to the accompanying drawings, forming a part of this specification. I

My invention relates to improvements in player pianos of the type wherein pneumatic motive power is employed.

It is the object of my present invention to conserve the power, to effect easy playing, by the elimination of useless waste and dissipation of energy.

The pneumatic system of a player piano, as is well known, is ordinarily made practically entirely, if not absolutely entirely, of wood, a considerable number of independently manufactured parts being assembled to form the ultimate structure. It is the aim of my invention to produce an absolutely air tight assembled structure. Just as a chain is no stronger than its weakest link, so is a pneumatic system no more efficient than its worst joint, and leakage at the joints is one of the prime difficulties with which the manufacturer of pneumatic player pianos has to contend.

My invention contemplates a structure wherein all joints, where, as experience has shown, leaks occur, (which means all or practically all joints) can be and are glued, forming a perfectly air-tight assembly, the structure and arrangement of parts whereby this desirable result is secured resulting in further desirable results in the way of simplicity, compactness, and solidity.

I am fully aware that it is old in the art to glue two wooden parts together in a pneumatic player piano, but in all cases in the prior art such practice has been followed only as to some of the joints, thus making these joints, so far as tightness was concerned, no more efiicient than the other joints, and then only as to joints where leaks were least likely to occur. This was invariably the case because the glue was employed only where, by reason of the nature of the parts and the assembly, gluing was permissible and inexpensive, the nature of many of the parts and the assembly being such a to provide for internal accessibility for replacement and adjustment, prohibitmg the use of glue. In these other joints screws and a compressible packing were employed to serve the double purpose of lending solidity and tightness to the structure. Due to the alternate swelling and shrinking of the wood, according to temperature and humidity, the packing becomes ineffective and leaks are certain to occur, and the manufacturer has come to consider such difiiculties as necessary evils.

By employing a structure in which all or practically all of the joints between pieces of wood can be and are glued, and casting aside the teachings of the prior art and gluing where glue could not be or was not used before, I am enabled to produce an absolutely air-tight structure with the attendant advantages above pointed out.

There may be an exception to this practice of gluing the joints where the nature of the parts joined makes a joint with screws and packing adequate, as where a relatively very small part is attached to a much larger part, or where a leak would contribute to ghe function which the parts already per orm.

My invention will be more readily under-' stood. by reference to the accompanying drawings in which Figure 1 is a front elevational view of a player piano embodying the features of my invention, the front panels being removed in order to disclose the interior construction;

Figure 2 is a front elevational view of the bellows board and the parts carried thereby, certain parts being removed in order more clearly to illustrate the construction; V

Figure 3 is a sectional view taken on plane of the line 3-3 of Figure 2 and looking in the direction indicated by the arrows;

Figure 4: is a sectional view taken on the plane of the line 4--&' of Figure 2 and looking in the direction indicated by the arrows;

Figure 5 is a sectional view taken on the plane of the line 55 of Figure 2 and looking in the direction indicated by the arrows;

Figure 6 is a rear elevational view of the pneumatic stack; and

Figure '7 is a sectional view taken on the planeof the line 7+7 of Figure 6 and looking the direction indicated by the arrows.

Similar reference characters are applied.

trolling the opening 18 being to the same parts throughout the various figures.

The power plant is suitably located within the casing below the l-:eyboard, the primary support thereo't' being the bellows board 8. Mounted upon this bellows board are the exhaust bellows 9, 9, the movable members 10, of which are glued to one portion of the hinge member 11, the other portion of the hinge member being glued to the block 13 whiclr in turn is glued to the bellows board 8; The bellows cloth 12 is glued to the member 10 and board 8 in each case. The bellows throat is in the form of a box comprising the top and bottom walls 15 the exhaust bellows 9, 9 through suitable openings, one of which is shown in Figure 4% and designated 18, a flap valve 19 for conglued between the block 13 and bellows board 8. A second valve 20 controls opening 21 in the movable member 10', said valve being maintained in closed position by a spring 32 anchored at 43 to the rear face of the movable member 10. A spring 24 anchored at engages the rear face of the movable member 10 and tends to maintain the same collapsed as shown in Figure 1.

In the present construction, the bellows are operated manually by a pair of pedals 27, 27, said pedals being pivoted at their outer ends on a frame 28 which is provided with side pieces 29 which are pivoted at 30; 30 to the bellows board Connection. had between the pedals 2?, 2'7 and the movable boards 10, 10 of the bellows 9, 9 by means of links 31, 31, pivoted at 32, 32 to the under. faces of the pedals 27, 2?, and at lows equalizers beingshown in Figure 3 and consisting'of a stationary member 46- which is rigid with the bellows board 8 and may be part thereof, the walls of the bellows throat being glued to these parts just as tliey'are' glued to the bellows board 8. Each bellows equalizer has a movable member (t7 whichis glued at its upper end to one part of a hinge 48 the other part of which is glued to the bl'oclt- 49 which, in turn, is glued at .50 to the stationary member-"4t.

The bellows cloth 51 of the bellows equalizer is glued to the stationary member 46 and movable member 4:7. The movable members l of the bellows equalizers are normally maintained distended as shown in Figure 3, by means of flat springs 5st, 51.

The motorexhaust tube 55 extends from the right hand end of the throat 1st and is in communication with the interior of the throat 11- through motor governor 56. The motor governor comprises a movable membe glued at one end to a hinge member 59 which, in turn, is glued to block 58. The block 58 is glued to the front face of the stationary member 46 of one of the bellows equalizers. A rectangular frame (30 defines the base or" the motor governor 56 and is glued to the front face of the stationary member #16, the bellows cloth 61 of the motor governor being glued to said frame and to the movable member 57. The motor governor is normally maintained in distended position, as shown in Figure 3, by n'ieans oi a flat spring 62 secured at 63 to the front wall 17 of the bellows throat, the "free end ol the spring engaging under a bracket 6-1" carried by the movable member 57.

The interior of. the motor governor 56 is in communication with the motor exhausttube through a duct 65 and is also normally in cou'nnunication with the interior of the bellows equalizers through a suitable opening 66. The opening 66 is controlled by a valve 6? carried by a valve stem 68 extending through the" opening 66, said valve stem being mounted on. the outer end of a lever 69 pivoted 70 on the front face of the stationary member 4- 6 within the motor overnor. The other end of the lever extends to a point near the top of the motor governor and is maintained in the position shown by means of acoil spring Tl seated between the end of: said lever and the member 46. A motor governor regulating screw 72' threads through the movable member 67 and engages the lever for regulating the stroke-0t the valve 6?. From the foregoing, it will be apparent that when the exhaust bellows are operated, a flow of air will be set up through the motor exhaust tube 55, chamber T6, duct 65, motor governor, opening 66, into the bellows equalizers 4-5, thence through the opening 4L3 to the bellows throat 14'.

A pair of partitions 73 and 74 are arranged at either end of the throat 14 to form compartments 7'5 and 76, communication being had between the compartments 75 and 76 and said throat 14; through suit able openings 7''? and 7 8 formed in said partitions. The openings 77 and 78 are adapted to be alternately closed by gate valve members 79 and 80, said gate valve members being pivotally mounted at 81 and 82 re the spectively, and having the free ends of the shafts thereof extending through the front all 17 of the throat 14.

As shown in Figure 1, levers 83 and at are carried by the outer ends of the gate valve shafts, and these levers are connected by a bar 85 termed re-roll thrust and valve connections, as will be described later. A spring 88 tends to hold said bar 85 toward the left hand end of its stroke.

Tubes 87 and 88 communicate with the compartments 73, the tube 87 serving the purpose of an exhaust tube for the channel board, which will be described later, and the tube 88 serving as the exhaust tube for the sustaining pedal pneumatic shown at 89 in Figure 1. The partitions in the bellows throat 1 1 are all glued in place to prevent leakage.

A tempo valve 90 is mounted on the right hand end of the throat 14: and servesto control the speed of the motor by varying the size of the passageway between tube and the motor governor, this valve being operable by a lever 91 adj ustably connected at 92 to the tempo lever 93, mounted below the keyboard.

The so-called re-roll pneumatic is de signated 94 and consists of a movable meirber 95 and a stationary member 96 joined by a bellows cloth glued thereto. The stationary member is glued to the valve block 09 which will be referred to later. The movable member 95 is connected by a link 97 to the lever 83. There-roll pneumatic is controlled by a valve, shown in Figure this valve being mounted in valve block 99 glued at 98 to the stationary member 16 of the equalizer. The valve block 90 is made of several parts glued together and forming the valve chamber 102 and the diaphragm chamber 100. The valve comprises a stem 105 passing through opening 101 and carrying a closure member 106 mounted thereon and adapted to close communication between the valve chamber 102 and the diaphragm chamber 100 by engagemeut with a ferrule 107 mounted in the opening. The chamber 100 is closed by a diaphragm 111 and is in communication with the bellows equalizer 141 by way of passageway 108. The valve stem 105 rests upon said diaphragm. A recess 109 below the diaphragm is adapted to be connected with the itmosphere by tube 110. Normally,.however, this recess is cut from atmosphere and the pressure on opposite sides of the diaphragm is balanced by way of the restricted bleeder 1. The chamber 102 communicates with the interior of the pneumatic 9 1 through a port 112, and the closure member 106 is adapted to seat alternately against the annular member 103 and against the ferrule 107. in the former position the re-roll pneumatic is connected with suction and in the latter with the atmosphere. A suitable protector 113 is mounted on top of the block to prevent the entry-of dust into the valve chamber. Collapsing of the pneumatic 94L closes the gate valve 7 9 and opens the gate valve 80 thereby shutting off the channel board and sustaining pedal pneumatic and shunting the suction around the motor governor to apply all of the suction developed in the throat lt to the pneumatic motor 1% whichis provided for-operating the rolls in the roller box 114. Suitable transmission gears 115 are simultaneously operated by the lever 9? in order to reverse the direction of the music sheet.

The power plant rests upon foot-screws 52 and 53 in the piano base.

As pointed out hereinbefore my present invention is concerned with the pneumatic system and I shall not, therefore, burden this description with detail explanation of the other parts. I will now refer to the pneumatic stack, so called, and pointout indetail my improved manner of constructing the same in accordance with my invention.

Referring now to Figures 6 and 7, it will be seen that there is provided a channel board 116 having a main channel 117 therein from wl ich suction is imparted to the various pneumatics mounted on the board. This channel 117 is formed by recessing the upper portion of the channel board to form two walls of the main channel 117 and then securing thereto a strip 118 of L-shaped cross section, said two parts being glued together.

Glued to the rear face of the channel board 116, at 129, are three valve shelves each of which contains a series of valve chambers and has glued thereto a respective series of striking pneumatics. Each pneumatic co-n'iprises a stationary element 120 and a movable element 123 joined by a bellows cloth 122 glued thereto. The movable member 123 is provided with an extension 12 1 which engages under the regulating or contact button 125 carried by the sticker or abstract 126. The stationary member 120 of the pneumatic is glued to the under face of the valve shelf 119 and said valve shelf is provided with a channel 127 which affords communication between valve chamber 128 and the interior of the pneumatic, the valve chamber being connected with the main channel 117, subject to the control of the valve 128, by way of the channel 127 and the vertical channel 130. The valve 128 carries a valve post or stem 131 and is flexibly connected thereto, said valve post extending through a. suitable opening 132 and having a disc 133 flexibly carried by the lower end thereof. The disc 133 rests upon the diaphragm 134 which closes off the diaphragm chamber 135. The diaphragm chamber 135 communicates through a duct 136 with the tracker channel 137 which ere of the diaphragm 134:.

tends up around the main channel 117 and through the member 118, said tracker channel having a tracker tube nipple 138 inserted into the end thereof and being connected with an opening in the tracker bar.

A disc 139 is mounted over the valve 128 and is provided With an opening 140, termed a pneumatic valve port of less diameter than that of the valve 128 so that When the valve raises, the same will close the said port 1 10. A blood hole l ll is provided in the channel board 116 to eli'ect restricted communication between the main channel 117 and the tracker channel 187 a bleed chamber 1 1 being provided adjacent the bleed hole 14-1, said chamber being closed againstleakage by means of a bleed hole cap 142 secured over the bleed chamber openings to the channel board.

The main channel 117 is connected directly to the throat 14-. through the channel board exhaust tube 87, so that suction is maintained in said channel 117 at all times. When the tracker bar opening is exposed by an aperture in the note sheet passing thereover, the suction communicated to the tracker channel. 187 through the bleed hole 1&1 is momentarily eclipsed by atmospheric pressure which becomes effective upon the under side As the suction in the channel 117 acts upon the upper side of the diaphragm 131, it will be raised, lifting the valve 128 off its seat and closing the opening 14-0, thereby transmitting suction from the channel 117 through the channels 127 and 127 to the interior of the pneumatic 121, thus collapsing, it and striking a note. A suitable protector 1421 is placed over the openings in the topof the valve shelt 119. As soon as the opening in the tracker bar is closed, suctionis reestablished in the tracker channel 137 and as the suction in this channel balances With the suction in' the channel 127 the diaphragm releases and the valve falls by gravity and by assistance of the suction in said chnnel 127 to close oli' suction from the pneumatic 121 and opens the same to atmosphere pern'iitting the pneumatic to expand.

In Figure 6 the arrangement of thepneu- 1 ratios in a stack on the rear of the channel board is shown, the pneumatics being staggered in order to facilitate connection to their respective stickers. The connection of the channed board exhaust tube is made by means of the nipple 1&5 shown in Figure (*1.

I claim:

in a player piano, a pneumatic stack comprising two Wood members oli L-shaped crosssection glued together to form a main channel extending longitudinally near the top thereof, said main channel having a plurality of vertical branch channels leading doWn \vardly from and lying entirely below said main channel, a plurality of narrow Wood valve shelves glued to said channel board and situated parallel to said main channel, said shelves each living a plurality of Valve chambers therein, and a plurality of strikpneumatics glued to each of said valve shelves, said shelves having communicating channels therein leading from each of said valve chambers to one of said branch channels and one of said pneumatics respectively.

In Witness whereof, I hereunto subscribe my name this 17th day of June A. D. 192

AXEL Gr.-GULBRANSEN. 

